A connector device for a fluid system for medical purposes is disclosed that includes a main housing having a fluid flow chamber forming two channel portions leading in different directions towards two open attachments, wherein the attachments are provided for connection to a fluid line or a fluid reservoir, and with an attachment port which opens into the fluid flow chamber and which has a closure arrangement and which includes a Luer connecting portion. The fluid flow chamber has a dimensionally stable flow-guiding wall which is arranged between the two channel portions in the fluid flow chamber and protrudes freely with a front edge towards the attachment port in such a way that the closure arrangement, upon opening of the closure arrangement, interacts with the front edge of the flow-guiding wall in order to effect flow of fluid out of the attachment port into only one channel portion.